how old was the kid? young kids spit up all the time with no warning. its possible the mother thought that it was one of those episodes and continued shopping not knowing that it might happen again? this is kinda a gross story but i was at walmart once and a baby started spitting up all over the floor with the biggest smile on his face! he obviously was not feeling sick at all cuz he was smiling and his mom didnt even notice. it wasnt until my boss went up to her with a kleenex that the mother noticed. its very possible that it was something like that